<html>
<head>
  <script>
   function displaySubMenu(li){
    var subMenu=li.getElementsByTagName("ul")[0];
   subMenu.style.display="block";
}	 
    function hideSubMenu(li){
      var subMenu=li.getElementsByTagName("ul")[0];
      subMenu.style.display="none";
}
 </script>
  <style>
*{
   padding:0;
   margin:0;
}
body{
    font-family:verdana,sans-seif;
    font-size:small;
}
#navigation,#navigation li ul{
  list-style-type:none;
}
#navigation{
   margin:20px;
}
#navigation li{
 float:left;
 text-align:center;
 position:relative;
}
#navigation li a:link,#navigation li a:visited{
   display:block;
  text-decoration:none;
  color:#00;
  width:120px;
  height:40px;
  line-height:40px;
  border:1px solid #fff;
  border-width:1px 1px 0 0;
  background:#c5dbf2;
  padding-left:10px;
}
#navigation li a:hover {   
            color:#fff;   
            background:#2687eb;   
        }   
        #navigation li ul li a:hover {   
            color:#fff;   
            background:#6b839c;    
        }   
        #navigation li ul {   
            display:none;   
            position:absolute;    
            top:40px;   
            left:0;   
            margin-top:1px;   
            width:120px;   
        }   
        #navigation li ul li ul {   
            display:none;   
            position:absolute;    
            top:0px;   
            left:130px;    
            margin-top:0;   
            margin-left:1px;   
            width:120px;   
        }   
  </style>

</head>
<body>
  <ul id="navigation">
     <li onmouseover="displaySubMenu(this)" onmouseout="hideSubMenu(this)">
    <a href="#">税控服务</a>
  <ul>
     <li><a href="#">税控盘申领</a></li>
     <li><a href="#">服务费缴费</a></li>
     <li><a href="#">税控服务器</a></li>
     <li><a href="#">软件下载</a></li>
     <li><a href="#">常见问题</a></li>
  </ul>
</li>
     <li onmouseover="displaySubMenu(this)" onmouseout="hideSubMenu(this)">
    <a href="#">企业服务</a>
<ul>
     <li><a href="#">企业捷算通</a></li>
     <li><a href="#">员工福利险</a></li>
     <li><a href="#">雇主责任险</a></li>
     <li><a href="#">机动车辆险</a></li>
  </ul>
</li>
     <li onmouseover="displaySubMenu(this)" onmouseout="hideSubMenu(this)">
    <a href="#">财税宝典</a>
<ul>
     <li><a href="#">财税操作</a></li>
     <li><a href="#">政策法规</a></li>
     <li><a href="#">财税要闻</a></li>
  </ul>
</li>
     <li onmouseover="displaySubMenu(this)" onmouseout="hideSubMenu(this)">
   <a href="#">财税问答</a>
<ul>
     <li><a href="#">开票软件</a></li>
     <li><a href="#">申报办税</a></li>
     <li><a href="#">发票咨询</a></li>
     <li><a href="#">其他</a></li>
  </ul>
</li>
  </ul>
</body>
</html>